Radio apparatus



June 11, 1940. A. BLMN 2 2 3 I RADIO APPARATUS I Filed Oct. 30, 1937 {sheets-sheet 1 Bnventor H Zbert- Blair! June 11,1940. BLAlN RADIO APPARATUS Filed Oct so,'-19s'r 2Sheets-Sheet 2 Q Srwentor Albert Blazln Patented June ll 1940 PATENT; OFFICE RADIO APPARATUS Albert Blain, PhiIadeIphiaQPa assignor to Radio Corporation of America, a corporation of Delaware implication October so, 1937, steam... 171,845

3 Claims. -(o1. ria -:53)

This invention relates to radio. apparatus andhas special reference to the provision of improvements in television receivers. l .sTheprior art is replete with television receiv-.

; ers of various construction and design. Thus, it

haspreviously been proposed. toprovide a cabinetwherein the image produced on the screen of a vertically mounted image tube is viewed in a mirror contained in a movable lid with which the cabinet. is provided, the loudspeaker being mounted at the front of the cabinet. Another receiver has theimage tube mounted in a horizontal position adjacentthe topuof the cabinet, while the loudspeaker is mounted adjacent the base, near the floor. Irrespectiveof the advantages claimedxfor these different constructions, it

. maybe said generally that they are objectioninvention.

inthe sound which accompanies-the image ,ap

pearsto emanate from the image 1 Another and. related objectof the inventionis tofprovide a novel tuning control mechanism which permits the tuner itself to be mounted at a remote point and the loudspeaker to be mounts ed adjacent the image tube in the space usually allotted to the main tuning condenser and its associated parts.

Other objects and advantages, together with certain details of construction, will be apparent and the invention itself will be best understood byreference to the following specification and to the accompanying drawings, wherein:

Figure lis a front plan View of a television receiver having the parts designed, positioned and arranged in accordance with theprinciple of the "Figure 2 is a frontelevational View, and

Figure 3 is anend'view of a condenser drive mechanism which is preferably employed in carrying the inventioninto effect. i

. Figure ,4 is a fragmentary view in perspective, and

.Figure 5 is an exploded view showing certain details of construction of the tuning mechanism.

more generallyshownin Figs. 1 to 3, inclusive.

In Fig. l, P designates generally the front panel ofa television cabinethaving a central axis indicated by the broken lines :r-:r. A'chassis B for the electrical apparatus is mounted within anated from the image.

the cabinet. Panel P is provided with three cutaway areas alongaxis :w-x to provide (a) an, aperture A in which the screen of a kinescope or other image tube K is framed, (b) an aperture A for a tuning scale D, and ,(c) an opening A through which sound from a-loudspeaker LS passes-and, adjacentthe top of which a tuning control shaft S is accommodated. As indicated the drawings, the geometrical center of' each of the parts K, D, S, and LS falls along, or is in register with, the central axis 12-41:. It will be. noted that the loudspeaker LS is here separated from the image tube merely by the. panel area necessary to accommodate the tuning scale D. Theresult is that sound from the speaker seems, to a nearby audience, as if it, in fact, em-

This desired impression is rendered possible because the cumbersome tuning condenser C isnotinterposed between the image and sound areas, but is mounted to one side of, and remote from the axis af-zr.

It might appear that the aural illusion above discussed might be more complete if the scale or dial D were likewise removed to one side or the other of the axis :c-a: and the loudspeaker placed still closer to the image tube. The ad-- vantage thus gained, however, isveryslight and ismorethan off-set by the sacrifice of symmetry in thefippearance of the cabinet; further, it is desirable that the dial, the image and the tuning knob be centrally arranged so that the operator may, ascertain (a) thetuning adjustment and (b) the imageadjustment at aqsingle glance.

The principal difficulty encountered in carrying the inventive concept of theinstant case into effeet was the provision of means ensuring an accurate indication of the angular position, or station frequency) towhich the main tuning condenser is adjusted. Considered from another aspect, the problem was toprovide a condenser driving mechanism, the operation of which would be characterized by. freedom from such back lash as would ordinarily arise (a) at thepoint where thedriving force istransferred to the coupling which necessarily extends from the tuning 45 control shaft to the main tuning shaft, and (b) at the point where the driving force is transferred from the coupling to the condenser shaft or its gear. .j i

.A mechanism which obviates the above de- .5 scribed-and other difficulties incident to the GOD'. trol ofa remotely disposed tuning device is shown in Figs. 2 to 5,inclusive. In these drawings B designates the chassis above whichthemain tuning shaft (see Fig. 3) of the set is conveniently mounted. Suitably coupled to shaft I as by a rubber spider 2 is a stub shaft 3 which is journaled in a bushing 4 which, in turn, is supported I by an upright extension 5 on an immovable bracket 6. A gear sector I fixed to the stub shaft as by a set screw 8 extends slightly beyond the front plane of the bracket. This bracket 6 is immovably fixed to the chassis B by ,a pair of arms or flanges 9 which are anchored to the chassis top as'by bolts ID.

The immovable bracket 6 is provided with two grooved lugs Il II which extend outwardly These grooved lugs sup- I The edge of one of the,

from its front surface. port a slotted rack I2. slots I2 in the rack fits the groove of lug II and the edge of the other slot I2 fits in the groove of the other lug II Cut away portions I2 and I2 which communicate with the I6 which is fixed as by spacers I1 and screws I8 to a dependent portion of the mounting bracket 6. I

When the knob Non the end of the control shaft S is turned, the pinion I will move the rack I2; when the rack I2 moves, the gear I on shaft 3 is rotated because its teeth mesh with the teeth I3 on the upper endsection I3 of the rack. Since the stub shaft 3 is coupled (by the spider 2) to the main tuning shaft I, theangular setting and hence the freque'ncy of the tuner may be adjusted as determined by the degree of rotation imparted to the tuning knob N.

Unless some take-up device is provided adjacent the point at which the pinion I5 meshes with the rack teeth Id and adjacent the point at which the gear "I meshes with the rack te eth I3 the main tuning shaft 3 will not move in perfect synchronism with the'control shaft S. To'pre- 'vent such lagf'or back lash two auxiliary toothed rack elements land 20 are affixed, respectively, to theupper (I3) and lower (I4) toothed end sections of the rack" I2 as by means of take-up springs I9 I9 'and 20 20 respectively. These take-up springs are accommodated in small slots which are provided for that purpose adjacent the opposite ends'of each of the paired toothed rack sections (I3 and I9, I4 and 20) and permit of a limited'range of movement therebetween. Thus, I9 may be moved with respect to I3, and ZI'Irnay be moved withrespect to I4, so that in assembling the device the 2,20s,s1 1 E 2I 2I which maintain the moving translucent-scale D in close proximity thereto. As describedin the above identified patent, the scale markings D have-a better light transmitting characteristicthan the surrounding portion of the scale and the translucent mask M is provided with a slot M of a suitable contour so that a,

, bright spot of light is superimposed upon each of the scale markings as the receiver is tuned throughout its tuning range;

Certain modifications of the invention will suggest themselves to those skilled in the art. It is to be understood, therefore, that the foregoing is to be interpreted as illustrative and not-in a limiting sense, except as required bythe prior art and by the spirit of the appended claims.

What is claimed is: v F? 1. A television"receiver comprising an image tube, a tuning control shaft and a loudspeaker mounted in closely spaced relation along a common axis, a tuner and a tuning shaft therefor mounted remote from said tuning control shaft and said axis, a driving gear on said control shaft, a driven gear on said tuning shaft, a rack having discrete toothed sections which mesh respectively with said gears, and means individual to said discrete toothed ra'ck sections for maintaining the teeth of each of said sections in intimate contact with the gear adjacent thereto.

2. A television receiver comprising an image tube, a tuning control shaft and a loudspeaker mounted in closely spaced relation along a common axis, a tuner having a tuning shaft mounted substantially parallel to andremote from said tuning control-shaft, a driving gear on said control shaft, a driven gear on said tuning shaft, a rack having discrete toothed sections which mesh respectively with said gears, and means comprising a separate toothed membermounted onv said rack closely adjacent said sections and relatively movable with respect thereto for maintaining said rack in energy transfer relation with said driving and drivengears. I

3. A television receiver comprising an image tube, a tuning control shaft, and a loudspeaker mounted in closely spaced relation along a com mon axis, a tuner and a tuning shaft mounted. substantially parallel to and remote from said tuning control shaft, a'dri'ving'gearon' saidcohtrol shaft, a driven gear on said tuning shaft, a

tooth rackfor transmitting a driving force between said control and tuning shafts, a pair of auxiliary toothed sectionsv mounted to permit} independent relative movement on-said rack and, positioned toxmesh. respectively with said gears, l, and means for separately biasing said relatively;

movable auxiliary rack sections whereby to main-j 1 tain the teeth thereon in mesh with said gearsfi v ALBERT BLAIN. 

